Question

What is the potential difference (in V) across each capacitor after switch $S$ is closed?

Answer 1

When switch S is closed the equivalent circuit will be as shown in figure.
$C_{eq1}=3+6=9\mu F$ and $C_{eq2}=6+3=9\mu F$
As $C_{eq1}$ and $C_{eq2}$ are in series and
$V_{ac}=\frac{9}{9+9}\times 360=180V$ and $V_{db}=\frac{9}{9+9}\times 360=180V$
As $(3,6)$ capacitors are in parallel for both loop so potential across each capacitor will be $180V$